Guns, including rifles, shotguns and pistols, often have a pair of sights, with one located near the front, and the other disposed toward the rear thereof. Sometimes, the front sight is a fixed member, and the rear sight is a blade, which may be raised or lowered adjustably, to conform to a desired line of sight relationship of the sights and target to the gun barrel The rear sight blade may be notched, or contain an aperture, to enable the user to align the rear sight with the front sight, along the barrel of the firearm.
Adjustability of the rear sight is often desirable, in order to permit the user to compensate for undesirable characteristics in the ballistic flight of the projectile. Such undesirable characteristics frequently result from manufacturing variations, or even defects. Moreover, improper or imprecise handling of the firearm can cause misalignment among the front and rear sights and the gun barrel.
It is recognized that, because there is often a great distance between the gun and the target, even minor variations in the position of the gun sight can have significant effects on the course of the bullet. As a result, adjustability of the rear sight is highly desirable to permit precise aiming alignment of the firearm at the target, and predictability in use thereof. Frequently, conventional firearms, such as rifles, are equipped with rear sights, which are manually adjustable for elevation. Such sights are oftentimes fixed in a trapezoidally shaped dovetail receptacle which is disposed transversely across the receiver of the firearm, near the stock. While such rear sights may be suitable for some applications, it is not uncommon for the shooter to replace the manufacturer-supplied rear sight with another, more precisely adjustable sight, in order to achieve greater accuracy in shooting.
In addition to precision of adjustment, the location and size of adjustable rear sights are very important considerations. In general, conventional rear sight adjustment mechanisms are located on the top of the gun barrel. As a result, such mechanisms must be compact in size and have a low silhouette design so as to permit a clear, unobstructed line of sight between the rear sight and the front sight Because of these factors, firearm rear sight adjustment mechanisms are generally intricate, complicated and expensive to manufacture. In addition, because of their complexity, they are all too frequently jarred out of proper adjustment. Moreover, the presence of moisture or grit during use in actual field conditions, can cause the sight adjustment mechanism to malfunction, or at least not function satisfactorily. This is especially the case if the mechanism is comprised of a number of small parts, all of which must cooperate precisely with each other in order for the sight to perform its alignment function in the desired manner. Therefore, it would be highly desirable to have a rear sight adjustment mechanism which would be relatively uncomplicated in design, capable of precise adjustment, and yet sufficiently durable to perform reliably under field conditions. At the same time, such a precisely adjustable gun sight should have a low silhouette, and should be relatively easy to adjust manually in field conditions.
Another important consideration in rear sight adjustment mechanism design relates to the effects of rough handling of the gun in the field. Because of such handling, adjustment mechanisms must be securely mounted to the firearm so as not to become dislodged or inadvertently jarred out of proper adjustment during use. Frequently, after a gun is purchased, the user elects to replace the manufacturer-supplied sight with a more desirable sight. In such cases, gunsmithing may be employed by the user to mount a sight adjustment mechanism irremovably on the firearm. Such gunsmithing can be an expensive technique, and it entails irreversible changes, such as tapping and threading screw holes, to the firearm. Owners of expensive firearms are frequently reluctant to have an expensive firearm permanently modified to accept a particular sight adjustment mechanism.
In addition to the need for rear sight elevational gun sights, the capability of lateral windage adjustment mechanisms in firearms is frequently desirable. Windage adjustments are useful in correcting for lateral deviations in the path of travel of the projectile. As in the case of elevational gun sight adjustment mechanisms, windage adjustment mechanisms have similar requirements for precision, reliability and predictability. For these reasons, windage sights are also complicated, expensive, sensitive, and easily damaged under field conditions. As a result, such sights are often unreliable under field use conditions. Because of such unreliability, many firearm manufacturers do not provide windage adjustments, and merely preset the rear sight for windage at the time of assembly of the firearm.
In some cases, conventional windage adjustments are sometimes so primitive and awkward as to comprise merely a sight, which is moved laterally for windage adjustment purposes, in a transverse dovetail slot, by means of a hammer and punch. Such an arrangement is clearly not precisely and accurately adjustable. Also, the adjustment cannot be made in a convenient manner. In view of the need for precise windage adjustment of firearms, it would be highly advantageous to have a rear gun sight which would have a windage adjustment capability, and which would be reliable, inexpensive to manufacture and capable of convenient, and yet sensitive windage adjustment under field conditions. Such a gun sight should be readily and conveniently adjustable for windage compensation purposes.
With further regard to field use, it is sometimes necessary for elevational and windage adjustments to be made in cold or wet weather conditions. In such conditions, it is desirable for the user to perform the adjustment while wearing gloves. It would be highly desirable to have such a gun sight which has the above mentioned characteristics, and which permits reliable and precise adjustment under adverse weather and lighting conditions.
Gun sights are known which are capable of both vertical and lateral adjustment for elevation and windage corrections. In this regard, reference may be made to U.S. Pat. No. 3,792,534 which discloses a gun sight in which axial adjustable movement is accomplished awkwardly, by loosening one screw, while tightening another one.
U.S. Pat. No. 4,628,611 discloses a gun sighting blade which is slidably mounted transversely relative to a sight body to provide windage adjustment capabilities by means of a sight adjustment screw. U.S. Pat. No. 4,575,961 discloses a gunsight elevating apparatus having a movable sight body, driven adjustably by a sight elevation adjusting screw which cooperates with the gun to move the sight body positionally adjustably relative thereto. However, the mechanisms disclosed in U.S. Pat. Nos. 4,628,611 and 4,575,961, require gunsmithing to mount the sight on the firearm.
The mechanisms disclosed in the foregoing patents, while providing elevation and windage adjustment capabilities, do not function entirely satisfactorily and reliably under adverse weather conditions during outdoor use. For example, the lock screw of U.S. Pat. No. 4,628,611 is very small and requires a screw driver or other blade type instrument for adjustment. In this regard, it would be very desirable to have an adjustable gun sight, which would function reliably and predictably under adverse outdoor field conditions, and which could permit precise rear sight manual adjustments, without requiring the use of a specialized tool.